Comparison of Delta FVC (% decrease in FVC at the PC(20)) between cough-variant asthma and classic asthma

J Asthma. Jan-Feb 2007;44(1):35-8. doi: 10.1080/02770900601034379.


The percentage decrease in forced vital capacity (FVC) at the methacholine PC(20) (Delta FVC) has been proposed as a surrogate marker of maximal airway response. The aim of this study was to compare the Delta FVC between patients with cough-variant asthma (CVA) and those with classic asthma (CA). We performed a retrospective analysis of methacholine challenge test data from 47 children who were diagnosed as having CVA and from 75 children who had CA of mild severity. The mean (+/- SD) Delta FVC was significantly (p = 0.001) lower in the CVA group (14.7 +/- 3.4%) compared with the CA group (17.1 +/- 4.4%), whereas PC(20) was not different between the two groups. Our results suggest that CVA is associated with a lower level of maximal airway response than CA.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Asthma / classification*
  • Asthma / physiopathology*
  • Bronchial Provocation Tests
  • Bronchoconstrictor Agents
  • Child
  • Cough / classification*
  • Cough / physiopathology*
  • Female
  • Humans
  • Male
  • Methacholine Chloride
  • Retrospective Studies
  • Vital Capacity


  • Bronchoconstrictor Agents
  • Methacholine Chloride